The invention relates generally to a hybrid nanostructured electrode material and its method of preparation for use in advanced rechargeable energy storage and power sources.
Many devices and applications rely on portable, rechargeable energy storage, or batteries. Some of these applications require both a reasonable supply of energy, as well as an occasional need for brief, high energy supply, or a pulse power. Automobiles using batteries often require a pulse of energy during acceleration, for example. Laser-powered flashlights may use both steady state and high energy pulse power for certain situations. Another application is in air and space vehicles, which require short periods of pulse power for thrust.
Current rechargeable electrochemical energy storage and pulse power sources have electrodes that exhibit higher than desired internal resistances and/or limited charge storage (active internal surface area) capacity. These limitations restrict the design of devices from simultaneously having both high power and high specific energy performance properties. As a consequence, situations with large energy demands and/or pulse power loads require oversizing batteries to meet application needs.
Advanced batteries taking advantage of new lithium chemistries have been investigated in the prior art, for example, lithium-nickel silicide nanowire anode technology (theo. capacity: 2,468 mAh/g vs a graphite anode capacity of 372 mAh/g). Key to achieving this performance level is the incorporation of a high specific surface area, low resistance graphene film with the silicide nanowire electrode. Another alternative is the silicon anode (theo. capacity 4,442 mAh/g) however, it's cycling performance is very limited.
Carbon nanotubes (CNTs) have provided enhanced performance in many technologies, however, while advanced CNT-based electrodes have lower resistance for pulse power uses, they also have limited Li (lithium) intercalation/adsorption capacity thus limiting their energy storage capacity. Graphene is another nanomaterial used for energy storage, however while graphene-based electrodes have a higher energy storage capacity, they also have lower electrical conductivity.
Thus, a need exists for improved electrode material for enhanced conductivity for advanced power sources having both high specific power (W/kg) and high specific energy (Whr/kg) performance.